A conventional shield excavator for excavating a tunnel has the cutter head which is disposed at the front portion of a shield body and rotatably driven by a cutter motor in which the cutter head has plural disk cutters which are rotatably provided at the front surface of the cutter head. When the cutter head is rotatably driven, these disk cutters excavate the working face.
The conventional disk cutter is, e. g. disclosed in Japanese Laid-Open Patent Publication No. 58-18497 in which a rotary cutter is fixed to a fixing seat in the steps of inserting a shaft supporter through an insertion groove defined on the fixing seat into a U-shaped notched portion of a rotary disk, inserting a spacer at the rear portion of the shaft supporter, turning a rotary portion 180.degree., attaching a presser member and fixing the presser member to the fixing seat by bolts.
In the conventional disk cutter, there was such a problem that the fixing portion has been large scaled since the height of the fixing seat should be increased in order to increase the strength of the fixing seat because of the insertion grooves in the fixing seat.
There was another problem that the structure is complex since many parts are necessitated for fixing the rotary cutter to the fixing seat and the rotary cutter drops when wheels are loosened by a load applied thereto in a rotary direction, thereby deteriorating its working efficiency or preventing the shied excavator from excavating further.
The present invention has been made to improve the problems of the conventional disk cutter and to provide a device for fixing the disk cutter to the shield excavator, which is simple in structure and reduced in the height in the fixing portion so as to be capable of fixing many disk cutters to the cutter head.